As is known, documents such as tags of differing nature and purposes may incorporate one or more readable codes in one or more rows in such a way that the code may be read by a data acquisition device linked to a computer, a printer, or the like without having to be read one by one by the operator, a procedure which is generally slower and error prone because such work is extremely tedious. Such a device is described in U.S. Pat. No. 4,988,853 of Nagashima. Another high-speed document-handling device is described in U.S. Pat. No. 4,962,623 of Francisco and U.S. Pat. No. 4,844,436 of Jaton.
Documents which should be so read are well known: bank checks coded with magnetic characters, perforated cards, and the like. Nevertheless, the must economical coding is by printing the codes as bar codes for which there are several standards. Bar codes are quite simple and compatible with tolerances admissible for the most common printing procedures. For these reasons, bar codes are widely used for the coding of information on goods for mass sale either by directly printing the bars on the containers or packaging or by the use of adhesive labels adhered on the goods. They are even used now for the coding of airline tickets.
If it were possible to read bar-coded documents, i.e. a printed sheet, by means of devices or machines capable of translating automatically and at great speed the information contained in the bar codes, this kind of documentation would be more extensively used, displacing from use in practice the more expensive codings currently employed where the economics of the operation is decisive. To date no machine has been proposed which can rapidly read bar codes off documents at a rate sufficient for many mass-marketing and similar purposes. Speeds in excess of about 400 documents/minute have not been obtainable.
In order to be able to read bar codes on products of mass use, there are reading devices adapted to capture the information from the variety of labels, containers, and the like. Hence their main characteristic is not their reading speed, but rather the positions and formats. Hand held optical readers, (sometimes named "optical pens") and scanners, some of which are capable of reading a single row of bars and ethers which can scan in more than one direction, are used. The latter are usually fixed and the coded article is displaced over the scanner, usually by hand. As to documents such as paper sheets or cardboard tags which convey information, to date there are no known means for reading automatically and at great speed vertical stacks of documents bearing these bar codes. The machines marketed as the Duplo USA NB-100 and Kowa LB130 can indeed pass bar-coded sheets past a reader, but operate at relatively low speeds, with a maximum throughput of about 500sheets/min or speed of 50M/min. The Duplo device uses two sets of feed belts which inherently puts a relatively low top limit on the speed the device can work at. When the Kowa device is driven at a 400 to 500sheets/minute rate it becomes highly failure prone, furthermore the Kowa machine cannot work from a large stack of sheets.
The prior-art devices take hold of each document, retain same against a vertical wall, displace the document on a horizontal path by means of rollers, and force the document to pass in front of a fixed reading head or scanner. These devices can work with these documents in this orientation because the documents are printed on stiff paper or cardstock due to the relative importance of the document, such as a check, airline ticket, selling tag, or the like. Therefore these slips or tags can stand on edge without collapsing. The problem with these vertically oriented documents is that the overall dimensions or area of the document cannot exceed determined dimensions because if it is too big the sheet cannot remain erect and will fold over because of its excessive weight.
Other devices are known, for example from U.S. Pat. No. 4,474,365 of DiBlasio, which can strip individual sheets from a stack of such sheets with the aim of counting them. While such devices work extremely rapidly, as they are invariably employed as bill counters, they are set up so that no scanning of any indicia on the bills is possible, since the bills travel over a very short path and are held virtually at all points along the travel path. Such a device also only works with relatively stiff paper.